Iron-Doped Nickel Molybdate with Enhanced Oxygen Evolution Kinetics.

Area of Science:

• Electrochemistry
• Materials Science
• Renewable Energy

Background:

• Electrochemical water splitting is crucial for renewable energy storage.
• The oxygen evolution reaction (OER) is a bottleneck due to its sluggish kinetics and high overpotential.
• Developing efficient, low-cost OER catalysts is essential for economical water electrolysis.

Purpose of the Study:

• To synthesize and evaluate Fe-doped NiMoO4 as a novel catalyst for the oxygen evolution reaction (OER) in alkaline media.
• To investigate the effect of Fe3+ doping on the electronic structure and catalytic activity of NiMoO4.
• To explore the potential of Fe-doped NiMoO4 as a cost-effective, precious-metal-free alternative for OER.

Main Methods:

• Synthesis of Fe-doped NiMoO4 (Ni0.9Fe0.1MoO4) and undoped NiMoO4.
• Electrochemical evaluation of catalytic activity for OER in 1 M KOH.
• Performance testing including overpotential measurements and chronopotentiometry.
• Ex-situ characterizations to identify the catalytically active sites.

Main Results:

• The optimal Ni0.9Fe0.1MoO4 catalyst achieved a current density of 10 mA cm-2 at an overpotential of 299 mV, which is 65 mV lower than that of NiMoO4.
• The catalyst demonstrated excellent stability during 2-hour chronopotentiometry testing.
• Ex-situ characterizations elucidated the catalytically active center in the Fe-doped material.

Conclusions:

• Fe doping effectively regulates the electronic structure of Ni centers in NiMoO4, enhancing OER catalytic activity.
• Fe-doped NiMoO4 presents a promising, precious-metal-free catalyst for efficient alkaline OER.
• The study expands the understanding of Fe-doping-induced synergistic effects in catalyst systems.